The present invention relates to an image regeneration device and an image regeneration method for regenerating image data of frames of a moving picture from code data which have been compressed according to a standard such as MPEG and stored in a record medium such as a CDROM, and in particular, to an image regeneration device and an image regeneration method in which a predetermined frame of the moving picture is displayed as a still image in the display of the moving picture.
In recent years, standardization has proceeded in techniques for digitally compressing moving pictures and still images. Among such standards is the standard by MPEG (Moving Pictures Expert Group).
FIG. 1 is a schematic diagram showing an example of the relationship between the image regeneration order and the display order of frames, in the case where code data (coded data) of the frames which has been compressed according to MPEG are regenerated (decoded) into image data of the frames and the frames are displayed. The I-frame (Intra-coded picture frame: the frame I1) shown in FIG. 1 is a frame which can be regenerated by use of its own code data only. The P-frame (Predictive-coded picture frame: the frame P4 or P7) shown in FIG. 1 is a frame which is regenerated by use of its own code data and by means of prediction referring to an I-frame or a P-frame of the past. The B-frame (Bidirectionally predictive-coded picture frame: the frame B2, B3, B5 or B6) shown in FIG. 1 is a frame which is regenerated by use of its own code data and by means of bidirectional prediction referring to an I-frame and/or a P-frame of the past and/or the future.
An example of the regeneration of the P-frames and the B-frames referring to other frames will hereafter be explained referring to FIG. 1. The frame P4 shown in FIG. 1 is a frame to be regenerated by means of prediction referring to the frame I1. The frame B2 is a frame to be regenerated by means of prediction referring to the frames I1 and P4. The frame B3 is also a frame to be regenerated by means of prediction referring to the frames I1 and P4. The display order (i.e. the order of display of the frames) is I1, B2, B3, P4, B5, B6, P7, . . . . However, the frames B2 and B3 have to be regenerated by means of the prediction using the future frame P4, and thus the frame P4 has to be regenerated before the frames B2 and B3. In the same way, the frames B5 and B6 have to be regenerated by means of the prediction using the future frame P7, and thus the frame P7 has to be regenerated before the frames B5 and B6. Therefore, the image regeneration order (i.e. the order of regeneration of the frames) becomes I1, P4, B2, B3, P7, B5, B6, . . . .
FIG. 2 is a graph showing the time-variation of the amount of code data of frames which are stored in a buffer circuit of an image regeneration device. The horizontal-axis of the graph indicates image regeneration of each frame. Compressing/regenerating method according to MPEG varies depending on the types of frames. As shown in FIG. 2, I-frames consume a large amount of code data (i.e. decrease the amount of code data stored in the buffer circuit) when regenerated, since the I-frame is regenerated by use of its own code data only and thus a large amount of its own code data is consumed. On the other hand, B-frames tend to store code data (i.e. increase the amount of code data stored in the buffer circuit) when regenerated, since the B-frame is regenerated by means of bidirectional prediction referring to image data of an I-frame and/or a P-frame of the past and/or the future and thus a little amount of its own code data is consumed.
As mentioned above, the amount of code data consumption in the buffers-circuit varies depending on the types of the regenerated frames, while data transfer rate between a record medium (CDROM etc.) and the buffer circuit is fixed. Therefore, in order to read out MPEG code data from the record medium at a constant data transfer rate and execute the image regeneration process smoothly, the buffer circuit for temporarily storing the MPEG code data of frames becomes necessary for avoiding overflow or underflow of the MPEG code data. For example, in cases where the underflow occurred and the buffer circuit became empty, the image regeneration process has to be suspended, and thereby the continuity or smoothness of display of the moving picture is necessitated to be deteriorated. Therefore, in order to avoid such troubles, the image regeneration process for the frames of the moving picture ought to be started after a certain amount of data has preliminarily been stored in the buffer circuit. In MPEG, the amount of code data which should be stored in the buffer circuit before the start of the regeneration process for the first frame is designated in xe2x80x9cVBV delayxe2x80x9d in the picture layer.
There have been established some standards for techniques for compressing moving picture data according to MPEG or CDROM-XA (Compact Disc Read Only Memory Extent Architecture) and storing the compressed data in sectors of a CD (Compact Disc). The video CD standard is one of such standards. In the video CD standard, an xe2x80x9cautomatic pause functionxe2x80x9d has been defined. In the automatic pause function, if an automatic pause trigger bit of a sector has been turned on, a frame corresponding to the sector keeps on being displayed by a display device as a still image until the automatic pause is released by the user.
FIG. 3 is a schematic diagram showing the structure of a sector of a CDROM according to CDROM-XA Form 2. As shown in FIG. 3, compressed code data corresponding to a frame is stored in one or more sectors of the CDROM. In FIG. 3, the automatic pause trigger bit with respect to a frame is placed in the sub-mode area in the sub-header of one of the sectors corresponding to the frame. Generally, compressed code data of a frame is distributed to a plurality of sectors and stored in user data areas of the sectors.
A technique which has been disclosed in Japanese Patent Application Laid-Open No. HEI7-226903 is known as a method for implementing the automatic pause function. FIG. 4 is a schematic block diagram showing the composition of an image regeneration control device which has been disclosed in the document. The image regeneration control device of FIG. 4 includes a reading circuit 32, a buffer circuit 33, a regeneration circuit 34 and a display circuit 35. The record medium 31 shown in FIG. 4 has a plurality of memory areas corresponding to sectors, and each of the sectors is provided with the sub-mode area and the user data area. The reading circuit 32 reads out code data which have been stored in the user data areas of the sectors of the record medium 31, and writes the code data in the buffer circuit 33. The buffer circuit 33 temporarily stores the code data written by the reading circuit 32. The regeneration circuit 34 reads out the code data from the buffer circuit 33, regenerates image data from the code data, and sends the image data to the display circuit 35. The display circuit 35 displays the image data supplied from the regeneration circuit 34.
In the record medium 31, code data necessary for the image regeneration is distributed to a plurality of sectors and stored in the user data areas of the sectors as has been shown in FIG. 3. If there is a frame to be displayed as a still image (i.e. a frame to be displayed according to the automatic pause function), the automatic pause trigger bit of the sub-mode area of the last sector corresponding to the frame (i.e. the last one of the sectors in which the code data of the frame is distributed and stored) is turned on.
The reading circuit 32 executes the reading of the code data from the record medium 31 successively in units of sectors, and sends the code data corresponding to each sector to the buffer circuit 33. FIG. 5 is a flow chart showing the reading operation of the reading circuit 32 of the image regeneration control device of FIG. 4. First, the reading circuit 32 reads out information stored in the sub-mode area of a sector (step 541). Subsequently, the reading circuit 32 reads out code data stored in the user data area of the sector (step S42), and writes the code data read out from the sector to the buffer circuit 33 (step S43). Incidentally, the reading circuit 32 does not necessarily read out all the code data stored in the user data area of the sector at once in the step S42. Subsequently, the reading circuit 32 judges whether or not code data reading from one sector has been completed (step S44). If code data reading from the sector has not been completed yet (xe2x80x9cNOxe2x80x9d in step S44), the reading circuit 32 returns to the step S42 and continues the code data reading from the sector and the code data writing to the buffer circuit 33. If code data reading from the sector has been completed (xe2x80x9cYESxe2x80x9d in step S44), the reading circuit 32 judges whether or not the automatic pause trigger bit of the sector has been turned on in the sub-mode area which has been read out in the step S41. If the automatic pause trigger bit of the sector has been turned on (xe2x80x9cYESxe2x80x9d in step S45), the reading circuit 32 stops the reading of sectors. If the automatic pause trigger bit of the sector has not been turned on (xe2x80x9cNOxe2x80x9d in step S45), the reading circuit 32 continues the reading of sectors, that is, returns to the step 41 and starts the next process for the next sector.
The buffer circuit 33 receives the code data corresponding to each sector successively from the reading circuit 32 and temporarily stores the code data. When the buffer circuit 33 has stored code data which are necessary for regenerating one frame, the buffer circuit 33 writes the stored code data to the regeneration circuit 34. If the buffer circuit 33 has not stored code data necessary for regenerating one frame yet, the buffer circuit 33 does not execute the writing to the regeneration circuit 34.
FIG. 6 is a flow chart showing the operation of the buffer circuit 33. Code data which has been read out from the record medium 31 in units of sectors by the reading circuit 32 is successively stored in the buffer circuit 33. In step S51, the buffer circuit 33 judges whether or not code data enough for regenerating one frame have already been stored therein. If code data enough for one frame have not been stored yet (xe2x80x9cNOxe2x80x9d in step S51), the buffer circuit 33 returns to the step S51 and thereby postpones code data writing to the regeneration circuit 34 until enough code data are stored. If code data enough for one frame have already stored (xe2x80x9cYESxe2x80x9d in step S51), the buffer circuit 33 writes the code data to the regeneration circuit 34 (step S52). Incidentally, the buffer circuit 33 does not necessarily completes the code data writing to the regeneration circuit 34 by one writing in the step S52. When the code data writing to the regeneration circuit 34 with respect to the frame is completed (xe2x80x9cYESxe2x80x9d in step S53), the buffer circuit 33 returns to the step S51 and starts the next process with respect to the next frame.
When the code data writing by the buffer circuit 33 with respect to one frame is completed, the regeneration circuit 34 executes regeneration of the frame using the code data. Thereafter, the regeneration circuit 34 transfers the regenerated frames to the display circuit 35 according to the predetermined display order rule (according to MPEG etc.).
FIG. 7 is a flow chart showing the operation of the regeneration circuit 34. If code data writing has been executed by the buffer circuit 33 (xe2x80x9cYESxe2x80x9d in step S61), the regeneration circuit 34 successively regenerates image data using the code data written by the buffer circuit 33 (step S62).
If image regeneration of one frame has been completed (xe2x80x9cYESxe2x80x9d in step S63), the image regeneration process for the frame is ended. The regeneration circuit 34 transfers the regenerated frames (i.e. image data of the frames) to the display circuit 35 according to the predetermined display order rule.
The display circuit 35 displays the frames (image data) supplied from the regeneration circuit 34 one by one in order of reception. When image data transfer from the regeneration circuit 34 is interrupted (due to the automatic pause trigger bit etc.), the display circuit 35 keeps on displaying the last frame from the regeneration circuit 34 as a still image until the image data transfer from the regeneration circuit 34 is started again, thereby the automatic pause display is executed.
In the following, the overall operation of the image regeneration control device of FIG. 4 will be described in detail.
First, a case where an automatic pause trigger bit of the last sector corresponding to a frame B5 (i.e. the last one of the sectors into which code data of the frame B5 has been distributed and stored) has been turned on as shown in FIG. 8 will be explained. Incidentally, FIG. 9 is a graph showing the time-variation of the amount of code data stored in the buffer circuit 33.
When the automatic pause trigger bit which has been turned on is found in the last sector corresponding to the frame B5, the reading circuit 32 writes code data which has been stored in the user data area of the sector into the buffer circuit 33 and thereafter stops reading of the following sectors. Now that the code data writing by the reading circuit 32 to the buffer circuit 33 has been stopped, the last frame that can be regenerated using the code data stored in the buffer circuit 33 is the frame B5 as shown in FIG. 8. The buffer circuit 33 sends the code data of the frame B5 to the regeneration circuit 34, and thereafter stops the code data writing to the regeneration circuit 34 since the buffer circuit 33 does not have enough code data for regenerating a frame any more. The regeneration circuit 34 executes image regeneration of the frame B5 using the code data, and sends the regenerated image data of the frame B5 to the display circuit 35 since display of the frame B5 becomes possible according to the display order rule of MPEG. Thereafter, the regeneration circuit 34 stops the image regeneration and stops sending image data to the display circuit 35 since no code data for the next frame is further supplied from the buffer circuit 33. The display circuit 35, which received the image data of the frame B5, displays the frame B5, and thereafter keeps on displaying the frame B5 as a still image since no image data for the next frame is further supplied from the regeneration circuit 34. Thereby, the automatic pause function is implemented.
When the automatic pause is released by the user, the regeneration circuit 34 can not restart the image regeneration process immediately since the buffer circuit 33 has not stored code data necessary for regenerating one frame yet, as shown in FIG. 9. Therefore, the regeneration circuit 34 has to wait until a certain amount of code data (necessary for stable image regeneration) are read out by the reading circuit 32 and stored in the buffer circuit 33. In the example of FIG. 9, the regeneration circuit 34 has to wait at least until code data for the next frame B6 is stored in the buffer circuit 33.
Next, another case where an automatic pause trigger bit of the last sector corresponding to a frame P7 (i.e. the last one of the sectors to which code data for the frame P7 is distributed and stored) has been turned on as shown in FIG. 10 will be explained.
When the automatic pause trigger bit which has been turned on is found in the last sector corresponding to the frame P7, the reading circuit 32 writes the code data which has been stored in the user data area of the sector into the buffer circuit 33 and thereafter stops reading of the following sectors. Now that the code data writing by the reading circuit 32 to the buffer circuit 33 has been stopped, the last frame that can be regenerated using the code data stored in the buffer circuit 33 is the frame P7. The buffer circuit 33 sends the code data of the frame P7 to the regeneration circuit 34, and thereafter stops the code data writing to the regeneration circuit 34 since the buffer circuit 33 does not have enough code, data for regenerating a frame any more. The regeneration circuit 34 executes image regeneration of the frame P7 using the code data. As a result, display of a frame P4 becomes possible according to the display order rule of MPEG, and thus the regeneration circuit 34 sends image data of the frame P4 to the display circuit 35. Thereafter, the regeneration circuit 34 stops the image regeneration process (for the next frame) since no code data for the next frame is further supplied from the buffer circuit 33. Due to the stop of the image regeneration process, image regeneration of frames B5 and B6 is not executed and thus image data of the frames B5 and B6 can not be transferred to the display circuit 35. Although image regeneration of the frame P7 has been completed, the regeneration circuit 34 can not send the image data of the frame P7 to the display circuit 35, since display of the frames B5 and B6 (which have to be displayed prior to the frame P7 according to the display order rule) has not been finished. Therefore, the display circuit 35, which received the image data of the frame P4 and displays the frame P4, keeps on displaying the frame P4 as a still image since image data of the next frame is not supplied from the regeneration circuit 34, although the frame P7 should be displayed as a still image according to the automatic pause function.
As explained above, the conventional image regeneration control device of FIG. 4 involves the following drawbacks or problems.
First, in the case of P-frames and I-frames, the display order of the frames becomes different from the image regeneration order. For example, in the case where a B-frame comes after an I(or P)-frame in the image regeneration order and the automatic pause trigger bit has been turned on in a sector corresponding to the I(or P)-frame, the reading circuit 32 does not read code data of the next B-frame, thereby the image regeneration of the B-frame (which should be displayed prior to the I(or P)-frame) is not executed by the regeneration circuit 34. Consequently, the automatic pause can not be correctly executed at the I(or P)-frame. Therefore, in order to execute the automatic pause at a correct frame, the position of the automatic pause trigger bit (i.e. the type of a frame in which the automatic pause trigger bit can be turned on) is necessitated to be limited.
Second, the buffer circuit 33 monitors whether or not there is a frame that can be regenerated, and executes the code data writing to the regeneration circuit 34 in units of frames. Therefore, the buffer circuit 33 has to be provided with the functions for managing the code data in units of frames, in addition to the ordinary function for temporarily storing the code data. In other words, complicated circuit composition becomes necessary in order to implement the functions of the buffer circuit 33 of the conventional image regeneration control device of FIG. 4.
Third, if the buffer circuit 33 stops its operation due to the execution of the automatic pause without having enough code data for regenerating one frame, the regeneration circuit 34 can not restart the image regeneration process even if the automatic pause is released by the user, until a certain amount of code data (necessary for stable image regeneration) are stored in the buffer circuit 33. Therefore, it takes some time between the release of the automatic pause and the display of the next frame.
Fourth, the automatic pause function in the image regeneration control device of FIG. 4 was implemented by letting the reading circuit 32 stop the code data writing to the buffer circuit 33 when the automatic pause trigger bit that has been turned on is found. Therefore, the sector in which the automatic pause trigger bit should be placed used to be limited to the last sector corresponding to the automatically paused frame.
It is therefore the primary object of the present invention to provide an image regeneration device and an image regeneration method, by which an identifier (an automatic pause trigger bit which has been turned on, etc.) of the automatic pause function can be detected correctly, and thereby the automatic pause display can be executed at a correct frame regardless of the type of the frame, that is, even in the case where the display order differs from the image regeneration order.
Another object of the present invention is to provide an image regeneration device and an image regeneration method, in which the buffer circuit for temporarily storing the code data which have been read out from the record medium can be implemented by a simple memory device.
Another object of the present invention is to provide an image regeneration device and an image regeneration method, by which quick restart of the image regeneration and display after the automatic pause can be realized.
Another object of the present invention is to provide an image regeneration device and an image regeneration method, by which the limitation in the position of the automatic pause trigger bit in the sectors corresponding to the automatically paused frame can be eliminated.
In accordance with a first aspect of the present invention, there is provided an image regeneration device for reading out code data of each frame of a moving picture which has been compressed according to a standard and stored in sectors of a record medium, regenerating image data of the frames using the code data according to the standard, and transferring the regenerated image data of the frames to a display device which displays the frames in order of reception, comprising a reading means, a temporary storage means and an image regeneration means. The reading means reads out the code data of the frames and additional information with regard to the code data from the sectors of the record medium. The temporary storage means temporarily stores the code data and the additional information which have been read out from the record medium. The image regeneration means reads out the code data and the additional information from the temporary storage means, regenerates image data of each frame using the code data according to the standard, and transfers the regenerated image data of the frames to the display device according to a predetermined display order rule. When the image regeneration means detected that a frame whose image data is to be transferred to the display device according to the display order rule has been designated by the additional information as an automatically paused frame, the image regeneration means stops its image regeneration process and suspends image data transfer of the next frame.
In accordance with a second aspect of the present invention, in the first aspect, the standard which is employed by the image regeneration means for regenerating the image data of the frames is MPEG.
In accordance with a third aspect of the present invention, in the first aspect, the image regeneration means stops its image regeneration process and thereafter stops the reading process of the reading means, when the image regeneration means detected that the frame whose image data is to be transferred to the display device according to the display order rule has been designated by the additional information as an automatically paused frame.
In accordance with a fourth aspect of the present invention, in the first aspect, the image regeneration means stops its image regeneration process and the reading process of the reading means almost simultaneously, when the image regeneration means detected that the frame whose image data is to be transferred to the display device according to the display order rule has been designated by the additional information as an automatically paused frame.
In accordance with a fifth aspect of the present invention, in the first aspect, the image regeneration means includes a first additional information storage means, an image memory means, a regeneration processing means and a transfer control means. The first additional information storage means stores the additional information with regard to the code data which has been read out from the record medium with the code data, stored in the temporary storage means with the code data, and read out from the temporary storage means. The image memory means stores the image data of the frames which have been regenerated using the code data according to the standard. The regeneration processing means reads out the code data and the additional information from the temporary storage means, regenerates image data of each frame according to the standard using the code data of the frame and referring to image data of frames which have been regenerated by the regeneration processing means and stored in the image memory means, stores the regenerated image data of the frame in the image memory means, and stores the additional information with regard to the code data of the frame in the first additional information storage means. The transfer control means reads out the regenerated image data of the frames from the image memory means and transfers the image data of the frames to the display device according to the predetermined display order rule, while referring to the additional information with regard to the frames which has been stored in the first additional information storage means in order to control the image data transfer. When the transfer control means detected that the frame whose image data is to be transferred to the display device has been designated by the additional information as an automatically paused frame, the transfer control means sends a regeneration stop request to the regeneration processing means so as to let the regeneration processing means suspend image regeneration of the next frame, completes image data transfer of the current frame, and suspends image data transfer of the next frame. When the regeneration processing means received the regeneration stop request, the regeneration processing means suspends image regeneration of the next frame, and sends a readout stop request to the reading means so as to let the reading means suspend its reading process with respect to the next sector.
In accordance with a sixth aspect of the present invention, in the fifth aspect, the reading means includes a second additional information storage means and a reading control means. The second additional information storage means stores the additional information with regard to the code data which has been read out from the sectors of the record medium. The reading control means reads out the code data and the additional information with regard to the code data from the record medium in units of sectors, stores the additional information with regard to the code data in the second additional information storage means, and transfers the code data to the temporary storage means. The second additional information storage means transfers the additional information with regard to the code data to the temporary storage means when the reading control means transfers the code data to the temporary storage means. When the reading control means received the readout stop request from the regeneration processing means of the image regeneration means, the reading control means stops the reading of code data and additional information from the record medium after completing the reading of code data of the current sector of the record medium.
In accordance with a seventh aspect of the present invention, in the sixth aspect, the temporary storage means is implemented by a FIFO memory for storing and outputting the code data supplied from the reading control means and the additional information with regard to the code data supplied from the second additional information storage means according to FIFO (first-in first-out) operation.
In accordance with an eighth aspect of the present invention, in the sixth aspect, the temporary storage means includes a data FIFO memory means, an address FIFO memory means and a comparator means. The data FIFO memory means stores the code data supplied from the reading control means. The address FIFO memory means receives the additional information with regard to the code data from the second additional information storage means, stores a write address of the data FIFO memory means into which the code data has been written if the additional information with regard to the code data designates the automatic pause display. The comparator means compares a write address outputted by the address FIFO memory means with a read address of the data FIFO memory means when code data is read out from the data FIFO memory means by the regeneration processing means, and outputs additional information designating the automatic pause display to the regeneration processing means if the write address matches the read address.
In accordance with a ninth aspect of the present invention, in the in first aspect, the image regeneration means includes a first additional information storage means, an image memory means, a regeneration processing means and a transfer control means. The first additional information storage means stores the additional information with regard to the code data which has been read out from the record medium with the code data, stored in the temporary storage means with the code data, and read out from the temporary storage means. The image memory means stores the image data of the frames which have been regenerated using the code data according to the standard. The regeneration processing means reads out the code data and the additional information from the temporary storage means, regenerates image data of each frame according to the standard using the code data of the frame and referring to image data of frames which have been regenerated by the regeneration processing means and stored in the image memory means, stores the regenerated image data of the frame in the image memory means, and stores the additional information with regard to the code data of the frame in the first additional information storage means. The transfer control means reads out the regenerated image data of the frames from the image memory means and transfers the image data of the frames to the display device according to the predetermined display order rule, while referring to the additional information with regard to the frames which has been stored in the first additional information storage means in order to control the image data transfer. When the transfer control means detected that the frame whose image data is to be transferred to the display device has been designated by the additional information as an automatically paused frame, the transfer control means sends a regeneration stop request to the regeneration processing means so as to let the regeneration processing means suspend image regeneration of the next frame, sends a readout stop request to the reading means so as to let the reading means suspend its reading process with respect to the next sector, completes image data transfer of the current frame, and suspends image data transfer of the next frame.
In accordance with a tenth aspect of the present invention, in the ninth aspect, the reading means includes a second additional information storage means and a reading control means. The second additional information storage means stores the additional information with regard to the code data which has been read out from the sectors of the record medium. The reading control means reads out the code data and the additional information with regard to the code data from the record medium in units of sectors, stores the additional information with regard to the code data in the second additional information storage means, and transfers the code data to the temporary storage means. The second additional information storage means transfers the additional information with regard to the code data to the temporary storage means when the reading control means transfers the code data to the temporary storage means. When the reading control means received the readout stop request from the transfer control means of the image regeneration means, the reading control means stops the reading of code data and additional information from the record medium after completing the reading of code data of the current sector of the record medium.
In accordance with an eleventh aspect of the present invention, in the tenth aspect, the temporary storage means is implemented by a FIFO memory for storing and outputting the code data supplied from the reading control means and the additional information with regard to the code data supplied from the second additional information storage means according to FIFO (first-in first-out) operation.
In accordance with a twelfth aspect of the present invention, in the tenth aspect, the temporary storage means includes a data FIFO memory means, an address FIFO memory means and a comparator means. The data FIFO memory means stores the code data supplied from the reading control means. The address FIFO memory means receives the additional information with regard to the code data from the second additional information storage means, stores a write address of the data FIFO memory means into which the code data has been written if the additional information with regard to the code data designates the automatic pause display. The comparator means compares a write address outputted by the address FIFO memory means with a read address of the data FIFO memory means when code data is read out from the data FIFO memory means by the regeneration processing means, and outputs additional information designating the automatic pause display to the regeneration processing means if the write address matches the read address.
In accordance with a thirteenth aspect of the present invention, there is provided an image regeneration method for reading out code data of each frame of a moving picture which has been compressed according to a standard and stored in sectors of a record medium, regenerating image data of the frames using the code data according to the standard, and transferring the regenerated image data of the frames to a display device which displays the frames in order of reception, comprising a reading step and an image regeneration step. In the reading step, the code data of the frames and additional information with regard to the code data are read out from the sectors of the record medium, and the code data and the additional information read out from the record medium is temporarily stored in a temporary storage means. In the image regeneration step, the code data and the additional information with regard to the code data are read out from the temporary storage means, image data of each frame is regenerated using the code data according to the standard, and the regenerated image data of the frames are transferred to the display device according to a predetermined display order rule. In the image regeneration step, if a frame whose image data is to be transferred to the display device according to the display order rule has been designated by the additional information as an automatically paused frame, the regeneration of image data is stopped and the image data transfer of the next frame is suspended.
In accordance with a fourteenth aspect of the present invention, in the thirteenth aspect, the standard which is employed in the image regeneration step for regenerating the image data of the frames is MPEG.
In accordance with a fifteenth aspect of the present invention, in the thirteenth aspect, if the frame whose image data is to be transferred to the display device according to the display order rule has been designated by the additional information as an automatically paused frame in the image regeneration step, the image data regeneration in the image regeneration step is stopped and thereafter the reading in the reading step is stopped.
In accordance with a sixteenth aspect of the present invention, in the thirteenth aspect, if the frame whose image data is to be transferred to the display device according to the display order rule has been designated by the additional information as an automatically paused frame in the image regeneration step, the image data regeneration in the image regeneration step and the reading in the reading step are stopped almost simultaneously.
In accordance with a seventeenth aspect of the present invention, in the thirteenth aspect, the image regeneration step includes a first storage step, a regeneration processing step, a second storage step and a transfer control step. In the first storage step, the additional information with regard to the code data, which has been read out from the record medium with the code data, stored in the temporary storage means with the code data, and read out from the temporary storage means, is stored in a first additional information storage means. In the regeneration processing step, the code data is read out from the temporary storage means, image data of each frame is regenerated according to the standard using the code data of the frame and referring to image data of frames which have been regenerated and stored in an image memory means. In the second storage step, the image data of the frames which have been regenerated in the regeneration processing step are stored in the image memory means. In the transfer control step, the regenerated image data of the frames are read out from the image memory means and the image data of the frames are transferred to the display device according to the predetermined display order rule, while the additional information with regard to the frames which has been stored in the first additional information storage means is referred to in order to control the image data transfer. If the frame whose image data is to be transferred to the display device in the transfer control step has been designated by the additional information as an automatically paused frame, image regeneration of the next frame is suspended in the regeneration processing step, image data transfer of the next frame to be transferred is suspended in the transfer control step after completing image data transfer of the current frame, and the reading of the next sector is suspended in the reading step after the image regeneration is suspended in the regeneration processing step.
In accordance with an eighteenth aspect of the present invention, in the seventeenth aspect, the reading step includes a third storage step, a fourth storage step and a fifth storage step. In the third storage step, the additional information with regard to the code data is read out from the record medium in units of sectors and stored in a second additional information storage means. In the fourth storage step, the code data is read out from the record medium in units of sectors and stored in the temporary storage means. In the fifth storage step, the additional information with regard to the code data which has been stored in the second additional information storage means is read out and stored in the temporary storage means. The storage of the additional information with regard to the code data in the temporary storage means is executed in the fifth storage step when the storage of the code data in the temporary storage means is started in the fourth storage step. The readout of the additional information and the code data in the third and the fourth storage steps are stopped after the image regeneration is suspended in the regeneration processing step.
In accordance with a nineteenth aspect of the present invention, in the thirteenth aspect, the image regeneration step includes a first storage step, a regeneration processing step, a second storage step and a transfer control step. In the first storage step, the additional information with regard to the code data, which has been read out from the record medium with the code data, stored in the temporary storage means with the code data, and read out from the temporary storage means, is stored in a first additional information storage means. In the regeneration processing step, the code data is read out from the temporary storage means, image data of each frame is regenerated according to the standard using the code data of the frame and referring to image data of frames which have been regenerated and stored in an image memory means. In the second storage step, the image data of the frames which have been regenerated in the regeneration processing step are stored in the image memory means. In the transfer control step, the regenerated image data of the frames are read out from the image memory means and the image data of the frames are transferred to the display device according to the predetermined display order rule, while the additional information with regard to the frames which has been stored in the first additional information storage means is referred to in order to control the image data transfer. If the frame whose image data is to be transferred to the display device in the transfer control step has been designated by the additional information as an automatically paused frame, image regeneration of the next frame is suspended in the regeneration processing step, the reading of the next sector is suspended in the reading step almost simultaneously with the suspension in the regeneration processing step, and image data transfer of the next frame to be transferred is suspended in the transfer control step after completing image data transfer of the current frame.
In accordance with a twentieth aspect of the present invention, in the nineteenth aspect, the reading step includes a third storage step, a fourth storage step and a fifth storage step. In the third storage step, the additional information with regard to the code data is read out from the record medium in units of sectors and stored in a second additional information storage means. In the fourth storage step, the code data is read out from the record medium in units of sectors and stored in the temporary storage means. In the fifth storage step, the additional information, with regard to the code data which has been stored in the second additional information storage means is read out and stored in the temporary storage means. The storage of the additional information with regard to the code data in the temporary storage means is executed in the fifth storage step when the storage of the code data in the temporary storage means is started in the fourth storage step. The readout of the additional information and the code data in the third and the fourth storage steps are stopped almost simultaneously with the suspension of the image regeneration in the regeneration processing step.